MFC r283441:

Implement epoll family system calls. This is a tiny wrapper
around kqueue() to implement epoll subset of functionality.
The kqueue user data are 32bit on i386 which is not enough for
epoll user data, so we keep user data in the proc emuldata.

Initial patch developed by rdivacky@ in 2007, then extended
by Yuri Victorovich @ r255672 and finished by me
in collaboration with mjg@ and jillies@.

1 files changed, 33 insertions, 2 deletions

diff --git a/sys/compat/linux/linux_emul.c b/sys/compat/linux/linux_emul.c
index 20eb8d1..78a1176 100644
--- a/sys/compat/linux/linux_emul.c
+++ b/sys/compat/linux/linux_emul.c
@@ -42,8 +42,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysent.h>
-#include <sys/sysproto.h>
-#include <sys/unistd.h>
 
 #include <compat/linux/linux_emul.h>
 #include <compat/linux/linux_misc.h>
@@ -86,6 +84,7 @@ linux_proc_init(struct thread *td, struct thread *newtd, int flags)
 {
 	struct linux_emuldata *em;
 	struct linux_pemuldata *pem;
+	struct epoll_emuldata *emd;
 
 	if (newtd != NULL) {
 		/* non-exec call */
@@ -93,8 +92,13 @@ linux_proc_init(struct thread *td, struct thread *newtd, int flags)
 		em->pdeath_signal = 0;
 		em->robust_futexes = NULL;
 		if (flags & LINUX_CLONE_THREAD) {
+			LINUX_CTR1(proc_init, "thread newtd(%d)",
+			    newtd->td_tid);
+
 			em->em_tid = newtd->td_tid;
 		} else {
+			LINUX_CTR1(proc_init, "fork newtd(%d)",
+			    newtd->td_proc->p_pid);
 
 			em->em_tid = newtd->td_proc->p_pid;
 
@@ -105,12 +109,24 @@ linux_proc_init(struct thread *td, struct thread *newtd, int flags)
 		newtd->td_emuldata = em;
 	} else {
 		/* exec */
+		LINUX_CTR1(proc_init, "exec newtd(%d)",
+		    td->td_proc->p_pid);
 
 		/* lookup the old one */
 		em = em_find(td);
 		KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
 
 		em->em_tid = td->td_proc->p_pid;
+
+		 /* epoll should be destroyed in a case of exec. */
+		pem = pem_find(td->td_proc);
+		KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n"));
+
+		if (pem->epoll != NULL) {
+			emd = pem->epoll;
+			pem->epoll = NULL;
+			free(emd, M_EPOLL);
+		}
 	}
 
 	em->child_clear_tid = NULL;
@@ -121,6 +137,7 @@ void
 linux_proc_exit(void *arg __unused, struct proc *p)
 {
 	struct linux_pemuldata *pem;
+	struct epoll_emuldata *emd;
 	struct thread *td = curthread;
 
 	if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
@@ -133,6 +150,12 @@ linux_proc_exit(void *arg __unused, struct proc *p)
 
 	p->p_emuldata = NULL;
 
+	if (pem->epoll != NULL) {
+		emd = pem->epoll;
+		pem->epoll = NULL;
+		free(emd, M_EPOLL);
+	}
+
 	sx_destroy(&pem->pem_sx);
 	free(pem, M_LINUX);
 }
@@ -141,6 +164,7 @@ int
 linux_common_execve(struct thread *td, struct image_args *eargs)
 {
 	struct linux_pemuldata *pem;
+	struct epoll_emuldata *emd;
 	struct linux_emuldata *em;
 	struct proc *p;
 	int error;
@@ -180,6 +204,12 @@ linux_common_execve(struct thread *td, struct image_args *eargs)
 		p->p_emuldata = NULL;
 		PROC_UNLOCK(p);
 
+		if (pem->epoll != NULL) {
+			emd = pem->epoll;
+			pem->epoll = NULL;
+			free(emd, M_EPOLL);
+		}
+
 		free(em, M_TEMP);
 		free(pem, M_LINUX);
 	}
@@ -197,6 +227,7 @@ linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
 	 */
 	if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
 	    SV_ABI_LINUX)) {
+
 		if (SV_PROC_ABI(p) == SV_ABI_LINUX)
 			linux_proc_init(td, NULL, 0);
 		else